Analysis of ALPS treated water as third-party
Purification process
(Source: Public Relation Documents of METI modified by JAEA)
Analysis results
ALPS treated water in K4-C tanks sampled on January 14, 2025
Analysis of nuclides other than tritium
As a result of the analysis of ALPS treated water before seawater dillution, the sum of ratios of legally required activity concentrations of radionuclides other than tritium (30 nuclides [Ref.]) was confirmed to be satisfy regulatory limit (less than 1).
The sum of ratios of the legally required activity concentrations of radionuclides: 0.072 < 1 (lower than 1)
In addition, nuclides othet than tritium (38 target nuclides [Ref.]) were confirmed not to be significantly present.
Analysis of tritium
The activity concentraion of tritium in ALPS treated water before seawater dillution was evaluated to be 310,000 Bq/L.
| Nuclide | Analysis value [Bq/L] | Uncertainty(k=2)*1 [Bq/L] |
|---|---|---|
| Tritium | 310,000 | ±27,000 |
When ALPS treated water is discharge into the sea, it is dilluted with seawater by TEPCO HD so that the tritum activity concentration is less than 1,500 Bq/L (1/40 of regulatory concentration limit).
*1 The uncertainty is the degree of variation in analytical value.
*2 The regulatory concentration limit (60,000 Bq/L) is defined as “the concentration at which the average dose rate would reach 1 mSv per year if a person continued to drink approximately 2 liters of water at that concentration every day from birth until the age of 70".
*3 Guidance level described in “Guidelines for drinking-water quality” (4th edition) by WHO (10,000 Bq/L) is defined as “the concentration that would result in an personal dose of 0.1 mSv if that concentration of water were drunk for one year”.
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The water in the discharge vertical shaft sampled on Mar. 10, 2025
Analysis of tritium
Tritium concentration after seawater dilution collected from discharge vertical shaft was confirmed to be 150 Bq/L.
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Reference: Analyte nuclides
